Title of Invention

OLEFIN POLYMERIZATION CATALYST COMPONENT, ITS PREPARATION AND USE

Abstract

A catalyst having high activity independent of the hydrogen concentration and low gel productivity in the polymerization of ethylene has been prepared. The preparation comprises the steps of reacting: a support comprising a magnesium halide compound having the formula (1): RO2-nMgXn (1) Wherein R is a CI-C20 alkyl, a C7-C26 aralkyl, a C1-C20 alkoxy or a C7-C26 aralkoxy, each same or different X is a halogen, and n is an integer 1 or 2, an alkyl metal halide compound having the formula (2): RlnlMmlXl(3ml-nl) (2) wherein Me is B or AI, each same or different R 1 is a C l-C 10 alkyl, each same or different X 1 is a halogen, m 1 is 1 or 2, n 1 is 1 or 2 when m 1 is 1 and n 1 is an integer from 1 to 5 when m 1 is 2, a magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide, said magnesium composition having the empirical formula (3): R2n2(R30)2-n2Mg (3) wherein each same or different R 2 is a C l-C20 alkyl, each same or different R 3 is a CI-C20 alkyl, n2 is between 0.01 and 1.99, and a titanium halide compound having the formula(4): (R40)n3TiX24-n3 (4) . wherein each same or different R4 is a CI-C20 alkyl, each same or different X2 is a halogen, n3 is 0 or an integer 1-3, and Ti is quadrivalent titanium.

Full Text

The Invention relates to a two-stage process for the polymerization of ethylene comprising a loop reactor stage and a gas phase reactor stage. Background of the invention Olefinic unsaturated monomers such as ethylene can often be polymerized in ttie presence of a catalyst composition, which has essentially two components: a compound of a transition metal belonging to one of groups 4 to 6 of the Periodic Table of Elements (Hubbardi lUPAC 1990) which is often called a procatalyst, and a compound of a metal belonging to any of groups 1 to 3 said Table which is often celled a cocatalyst. This kind of Ziegler-Natta catalyst composition has been further developed by depositing the procatatyst on a more or less inert and particulate support and by adding to the catalyst composition in the stages of its preparation several additives, among others electron donating compounds. These compounds have Improved the polymerization activity of the catalyst, the operating life and other properties of the catalyst composition and first of all properties of the polymers which are obtained by means of the catalyst composition. When ethylene polymers are produced, the polymer molecules formed are not simitar by molecular weight, but a mixture having a narrow or broad molecular weight distribution Is developed. The broadness of the molecular weight distribution may be described by utilization of the ratio of two different averages, namely the weight average molecular Mw and the number average molecular weight Mru where a high value of Mw/Mn indicates a broad molecular distribution. For controlling the molecular weight a so called chain transfer agent can be added to the polymerization reaction mixture. In order to obtain polymer products having different molecular weights, different amounts of the chain transfer agent for controlling the molecular weight must be fed into the polymerization reaction mixture. The most usual and preferable chain transfer agent is hydrogen, because when using it no foreign atoms or atom groups are left in the growing molecule, that would cause inconveniencies for the polymerization process or disadvantageous properties of the polymer produced. How well the molecular weight of the produced polymer varies as function of the hydrogen amount, I.e. how much the so called hydrogen sensibility changes, greatly depends on the catalyst composition. Generally the problem is, that In polyethylene production the polymerization activity decreases to quite an extent the more hydrogen is present. This absence of catalyst activity balance is a common drawback for all prior art catalysts today. The imbalance shows up when, using prior art catalysts, a drastic drop in the productivity of the catalysts occurs when going from polymerization conditions giving high molecular weight polymers (low melt flow rate) to polymerization conditions giving low molecular weight polymers (high melt flow rate). Even if such a commercial catalyst can have a quite good productivity at a polymer melt flow rate (MFR, defined according to standard ISO 1133) of 1, there is often only 10% left of the productivity when producing a MFR of 500. Thus It is desirable to provide a catalyst system having a high activity which is independent of the molar mass of the polymer under formation. The activity balance discussed above is Important In production of bimodal polyethylene. There, a low molecular weight component is produced in one stage at a high hydrogen concentration and a high molecular weight component Is produces in another stage at a low hydrogen concentration. Since no fresh catalyst is added between these polymerization stages, the catalyst employed in production of bimodal polyethylene must be able to produce the different molecular weights with a high productivity. EP-A-32307 discloses a procataiyst that has been prepared by treating an Inorganic support like silica with a chlorlnatlon agent like ethyl aluminum dichlorlde which support is then contacted with a magnesium alkyl compound like butyl ethyl magnesium, and with titanium tetrachloride (see claim 1, example 1, table 1). WO-A-96/05236 discloses a catalyst component comprising (i) a particulate support where the majority of particles is In the form of an agglomerate of sub particles and (ii) a magnesium haiide. The publication discusses the preparation of the support material. It also describes catalyst preparation and polymerization examples, The catalyst is prepared by adding titanium tetrachloride and D6AC on the agglomerated carrier containing magnesium chloride. The polymerization examples show that a higher bulk density and a higher MFR (better hydrogen response) as well as a lower FRR (narrower molecular weight distribution) is obtained by the catalyst prepared according to the disclosure. The publication does no refer to the homogeneity of the material. EP-A-688 794 discloses a process for the preparation of a high activity procataiyst, wherein an inorganic support is reacted with an alkyl metal chloride^ the first reaction product is reached with a compound containing hydracarbyl and hydrocarbyl oxide linked to magnesium, and the obtained second reaction product is contacted with a titanium chloride compound. The obtained procataiyst has good activity both at high and tow MFR polymerization conditions, but It has the drawback of giving an Inhomogeneous ethylene polymer product, resulting in gels and white spots In the polymer material. These inhomogenities have detrimental effect on the appearance and mechanical properties of polyethylene film. Description of the invention The drawbacks encountered by EP-A-688 794 and other prior art catalysts have now been eliminated by a modified ethylene polymerization process, Wherein a polyethylene composition, which has a molecular weight distribution expressed as SHI 5/3001 which is the ratio of the complex viscosity at a complex modulus value of 5 kPa to the complex viscosity at a complex modulus value of 300 kPa of higher than 60 and a low gel level meaning that when a film is made of the polyethylene composition It has a number of gels in the size class 0.3 - 0.7 mm of lower than 20 for a film area of 210 mm by 297mm, and no gels of larger size than 0.7mm, is produced by means of a high activity catalyst component, prepared by the steps of reacting: a support comprising a magnesium halide compound having the formula (1): By 'magnesium composition* above is meant a mixture or a compound. Note that formula (3) Is an empirical formula and expresses the molar amounts of alkyl R2 and atkoxy OR3 relative to the amount of magnesium Mg, which has been defined as 1, and differs from formulas (1), (2) and (4), which dlsclose the molecular composition of distinct compounds only. A procatalyst has now been discovered by which ethylene homopolymers or copolymers having low or high molecular weights can be produced with an even and high activity as well as a homogeneous consistence, Independently of the amount of hydrogen introduced into the polymerization reactor, the activity of the catalyst remains more or less unchanged and a homogeneous ethylene polymer product is obtained. The unique feature of the catalyst according to the invention now lies over its good balance in activity and a homogeneous product in a very wide range of molar mass regulating hydrogen partial pressures used in the polymerization of ethylene. It is thus possible to carry out an ethylene polymerization by the use of this catalyst at high and tow melt flow and still have very similar high productivity as well as a homogeneous, gel free product. This MFR/activity balance renders the catalyst universally applicable for most types of PE resins in ail polymerization processes using heterogeneous catalyst systems. Preferably, the preparation of the catalyst component comprises the subsequent steps of, a) providing said support comprising a magnesium hatlde compound having the formula (1), b) contacting said support comprising a magnesium halide compound having the formula (1) with said alky I metal halide compound having the formula (2), to give a first product, c) contacting said first product with said magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide and having the empirical formula (3), to give a second product, and d) contacting said second product with said titanium halide compound having the formula (4). The support used in the process is preferably in the form of particles, the size of which is from about 1pm to about 1000 µm, preferably about 10 µm to about 100 um. The support material must have a suitable particle size distribution, a high porosity and a targe specific surface area. A good result is achieved If the support material has a specific surface area between 100 and 500 mVg support and a pore volume of 1-3 ml/g support. According to another embodiment of the Invention, the support comprising a magnesium hailde compound having the formula (1) also comprises an Inorganic oxide. Several oxides are suitable, but silicon, aluminium, titanium, chromium and zirconium oxide or mixtures thereof are preferred. The most preferred inorganic oxides are silica, alumina, silica-alumina, magnesia and mixtures thereof, uttermost preferably silica. The Inorganic oxide can also be chemically pretreated, e.g. by sllylation or by treatment with aluminium alkyls. It is recommendabie to dry the inorganic oxide before impregnating it by other catalyst components. A good result is actieved if the oxide is heat-treated at 100°C to 900°C for a sufficient time, and thereby the surface hydroxyl groups, in the case of silica, are reduced to below 2 mmol/g Sl02. According to this aspect of the invention, the support comprises particulars having a core comprising said Inorganic oxide and a shell comprising said magnesium hailde compound having the formula (1). Then, the support comprising a magnesium hailde compound having the formula (1) and an inorganic oxide can conveniently be prepared by treating particulars of the inorganic oxide with a solution of the magnesium hallde and removing the solvent by evaporation. When using a support containing both said magnesium haiide compound (1) and another component, the amount of magnesium haiide compound (1) Is such that the support contains form 1 to 20% by weight, preferably from 2 to 6% by weight, of magnesium. The invention further comprises a step of reacting an alkyl metal haiide compound of the formula (2): The alkyl metal haiide compound Is preferably deposited on the support material. An even deposition is preferably achieved if the viscosity of the haiide or its solution is below 10 mPa*8 at the temperature applied. To achieve this low viscosity the alky I metal haiide can be diluted by non-polar hydrocarbon. The best deposition is however achieved if the total volume of the absorbed alkyl metal haiide solution is not exceeding the pore volume of the support. A good choice is to use a 5-25% hydrocarbon solution of ethyl aluminium dichloride. The number of additions of the hallde is preferably adjusted so that the technique are of not exceeding the pore volume at any additions is not violated, thereby giving an even distribution of the chemical in the surface of the support material. In the above mentioned preferred order of reaction steps a) to d), step b) can advantageously be performed so that undiluted alkyt metal haiide (2) is used to treat the support comprising a magnesium haiide compound having the formula (1). Alternatively, the support is contacted with a solution of the alkcyl metal haiide compound having the formula (2) in an essentially non-polar solvent, preferably a non-polar hydrocarbon solvent, most preferably a C4-C10 hydrocarbon. The concentration of the atkyl metal hallda compound having the formula (2) in said non-polar solvent is usually 1-80% by weight, preferably 5-40% by weight, most preferably 10-30% by weight. Advantageously, the support is contacted with a solution of said alky I metal haiide compound (2) in a ratio mol of the aikyi metal haiide compound (2) to grams of the support of between about 0.01 mmol/g and about 100 mmol/g, preferably between about 0.5 mmol/g and about 2.0 mmol/g. The amount of reactants can also be expressed as molar ratio, whereby it is advantageous, if the molar ratio of said alkyi metal haiide compound (2) to said magnesium haiide compound (1) of the support is between about 0.01 mol/moi to about 100, preferably about O.lmol/mol to about 10, most preferably from about 0.2 to about 3.0. In step b), the temperature at said contacting Is e.g. 5-80°C, preferably 10-50°C, most preferably 20-40'C. The duration of said contacting is 0.1-3h, preferably 0.5-1.5 h, In the claimed process, the magnesium composition containing magnesium bonded to a hydrocarbyi and magnesium bonded to a hydrocarbyl oxide and having the empirical formula (3), each some or different R2 Is preferably a C2-C10 alkyi, most preferably a C2-C8 alkyl. Each same or different R3 is preferably a C3-C20 alkyi, more preferably a branched C4-C10 alkyi, most preferably a 2-ethyl-l-hexyl or a 2-propyl-l-pentyl. The magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide and having the empirical formula (3) can also be defined by its preparation. According to one embodiment of the invention, it is a contact product of a dialkyl magnesium having the formula (S): Wherein each same or different R2 Is defined as above, and an alcohol. Preferably, the dlalkyl magnesium having the formula (5) Is dibutyt magnesium, butyl ethyl magnesium or butyl octyl magnesium. The magnesium composition can thus be defined in that the magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide having the empirical formula (3) is a contact product of a diatkyl magnesium and an atchohol having the formula (6): Wherein each same or different R3 is the same as above, preferably, the alchohol having the formula (6) Is a 2-alkanol, most preferably 2-ethyl hexanol or 2-propyi pentanol. It has been found that such branched alcohols give better results than linear alcohols. Preferably, the magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide having the empirical formula (3) Is a contact product of a dialkyi magnesium and an alcohol on a molar ratio alcohol to dialkyi magnesium of 0.01-100 mot/moi, preferably 1.0-5.0 mol/mol, more preferably 1.7-2.0 mol/mol, most preferabiy 1.8-1.98 mol/mol. The dialkyi magnesium and the alcohol are conveniently contacted by adding the alcohol to a solution of said dialkyi magnesium in an organic solvent, e.g. a C4-'C10 hydrocarban, Then, the concentration of the solution is preferably between 1 and 50% by weight, most prefarabiy between 10 and 30% by weight. The contacting temperature between the dialkyi magnesium and the alcohol is preferably 10-50°C, more preferably from about 20*C to about 35*C. In step c) of the above mentioned preferred order a)-»d) of the claimed process, the contacting product of the support with the alky I metal hallde compound (2) (asald first product) is contacted with said magnesium composition containing magnesium boned to a hydrocarbyl and magnesium boned to a hydrocarbyl oxide and having the empirical formula (3). Preferably, said first product is contacted with said magnesium composition (3) in a ratio moles of magnesium/g of the support of between 0.0001-1000 mmoi/g, preferably 0.01-100 mmol/g, most preferably 0.1-10 mmol/g, (g of the support means, in the case of said first reaction product, the support which was used as starting material for the first reaction product). A good deposition of said magnesium composition as a solution is achieved of the volume of the magnesium composition (3) solution Is about two times the pore volume of the support material. This is achieved if the concentration of the composition in a hydrocarbon solvent Is between 5-60% in respect of the hydrocarbon used. When depositing the magnesium composition on the support material its hydrocarbon solution should have a viscosity that Is lower than 10 mPa*s at the temperature applied. The viscosity of the magnesium complex solution can be adjusted for example by the choice of the group R4 in the formula (3), by the choice of the concentration of the hydrocarbaon solution, by the choice of the ratio between the magnesium alky I and the alcohol or by using some viscosity lowering agent. The titanium compound can be added to the support material with or without a previous drying of the catalyst to remove the volatile hydrocarbons. Remaining hydrocarbons can if desired be removed by using slight under pressure, elevated temperature or nitrogen flash. In the claimed process, the transition metal compound is a titanium hallde compound having the formula (4). R4 Is preferably a C2-C8 elkyl, most preferably a C2-C6 alky I. X2 is preferably chlorine and, Independently, n3 Is preferably 0. Said titanium halide compound having the formula (4) is advantageously titanium tetrachloride. According to one embodiment of the invention, in addition to said titanium compound having the formula (4), a titanium compound having the formula (7): Wherein each same or different R5 Is a C1-C20 atkvl, preferably a C2-C8 alkyl, most preferably a C2-C6 alkyl, each same or different X3 Is a halogen, preferably chlorine, n* Is an Integer 1-4, and Tl Is quadrivalent titanium, Is reacted. The titanium compound (7) always has at least one alkoxy group, which helps dissolving the titanium compound (4) which does not necessarily contain alkoxide, into an organic solvent before the contacting. Naturally, the more alkoxide groups compound (4) has, the lass is the need for compound (7), If compound (7) Is used, the preferable combination is that of titanium tetrachloride and a titanium tetre C1-C6-atkoxide. In step d) of the preferred step sequence a)->d), said second product is advantageously contacted with the titanium compound having the formula (4) In a ratio moles of said titanium compound/g of the support of 0.01-iO mmol/g, preferably 0.1-2 mmol/g. Preferably, said second reaction product Is contacted with said titanium compound (4) In a ratio moles of said titanium compound (4)/moles of the magnesium compound (3) of 0.05-2 mol/mol, preferably 0.1-1.2 mol/mol, most preferably 0.2-0.7 mol/mol. The temperature Is usually 10-80'C, preferably 30-60'C, most preferably from about 40°C to about 50°C, end the contacting time is usually 0.5-10 h, preferably 2-8 h, most prefferably from about 3.5 h to about 6.5 h. Above, the process for the production of ethylene polymer composition having a homogeneous consistence has been described in detail. The invention also relates to such a high activity catalyst component. The suitability for both low and high molecular weight polymerization means, that the claimed catalyst component has high activity both when producing low melt flow rate ethylene polymer and high melt flow rate polymer. High molecular weight polymer has high melt viscosity, I.e. low melt flow rate, and low molecular weight polymer has low melt viscosity, i.e. high melt flow rate. Simuitaneousiy or separately, it preferably produces ethylene homopoiymer and copolymer with low gel content. Most preferably it produces ethylene homopoiymer having a Gel number, measured under specified test conditions, of approximatively 0/0 1/m2. This means, that by the standards used, the claimed catalyst components can be used to produce totally homogenous (geiless) low and high molecular weight ethylene polymer. The invention also relates to the use of a catalyst component according to the invention in the polymerization of olefins, preferably in the homo - or copolymerization of ethylene. The advantage of the use is based on the fact that the claimed catalyst is suitable for both low molecular weight and high molecular weight ethylene polymerization and that the ethylene polymer produced is of high quality. In the polymerization, said alkyl metal haiide compound of the formula (2) can, if used, also act completely or partially as a cocatalyst. iHowever, it is preferable to add a cocatalyst having the formula (9); Wherein R6 is a C1-C20 alkyl, preferably a C1-C10 alkyl, most preferably a C2-C6 alkyl such as ethyl, X is a halogen, preferably chlorine, n is 1 to 3, more preferably 2 or 3, most preferably 3, to the polymerization mixture. The cocatalyst having the formula (9) is optional depending on whether said alkyl metal haiide compound (2) Is acting as cocatalyst or not. Experimental Part Some Factors Influencing the Gal Laval Those familiar with the art know that the level is influenced by two properties of the polymer, the average molecular weight (for which the melt flow rate, or MFR, is an often used measure) and the broadness of the molecular weight distribution (for which the shear thinning index, or SHI, and the flow rate ratio, or FRR, are often used measures). A high molecular weight (or, a low MFR) usually results in a higher gel level than a low molecular weight (or, a high MFR). Also, a broad molecular weight distribution (or, a high SHI or s FRR) usually results in a higher gel level than a narrow molecular weight distribution (or, a low SHI). Film Blowing Pelietized material samples were blown to a film on a pilot film line. The film blowing conditions were: Die diameter 30 mm Die gap 0.75 mm Blow-up ratio 3.0 A sample of the size 210 mm X 297 mm was cut froma film blown on the Collin line. The film sample was put into a gel scanner, which classifies the gels according to their size. The scanner gives the number of gels in three size classes, 0.7 mm. Generally the number of gets in the smallest class can be affected by different random factors, so often only the numbers of the intermediate (0.3...0.7 mm) and large (>0.7 mm) gels are given. The dispersion indicates the homogeneity of the blade samples in a similar fashion as the gel level indicates the homogeneity of the film samples. It is measured from the black pellets according to the ISO/OIS 11420 method as follows: Six pellets are cut using a microtome to 20µm cuts. Using an optical microscope, the white spots seen in the sample are then measured and classified according to their size. The average number of white spots In each size class is calculated. An ISO value indicating the dispersion is attributed to the material. A high ISO rating denotes a poor homogeneity (Large inhomogeneities). 7.9 g (60.8 mmol) of 2-ethyl-l-hexanol was added slowly to 27.8 (33.2 mmol) of 19.9% butyl-octyl-magnaslum. The reaction temperature was kept under 35'C. This complex was used In the following catalyst preparations. 2-ethyl-1-hexanol/butyl-octyl-magneslum ratio is 1.83:2. 8.6 g (66.4 mmol) of 2-ethyl-l-hexanol was added slowly to 27.8 (33.2 mmol) of 19.9% butyl-octyl-magnesium. The reaction temperature was kept under 35'°. This complex was used in the following catalyst preparations. 2-ethyl-l-hexanol/butyl-octyl-magneslum ratio Is 2:1. Comparative Example 1: Production of the Film Material The polymer samples were produced in a continuously operating pilot plant as follows: Tha catalyst used in this example was one known In the art, prepared according to patent application EP-A-688794 on a 40 µm silica carrier. The catalyst was fed into a 50 d3' loop prepolymerizatlon reactor, where a small amount of polymer was formed on the catalyst particles. The slurry containing the prepolymer was taken out of the reactor and passed into a 500 dm3 loop reactor. There the reactor conditions were set so that ethylene homopolymer with MFR2=500 was formed at a rate of about 25 kg/h. The polymer slurry was taken out of the loop reactor into a flash unit, where the hydrocarbons were separated from the polymer. The polymer was then passed Into a gas phase reactor where the polymerization was continued at a rate of about 35 kg/h. The reactor conditions were set so that MFR21 of the polymer collected from the reactor was about 9 and the density about 946 kg.m3 The powder was then collected and blended with additives after which it was palletized. A film was then blown from a pellet sample and the gel level was determined as described above. Table 1 shows some data of the material. 6.0 g (1.6 mmol/g carrier) of 20% EADC was added to 5.9 g of sylopol 2212 silica carrier. The mixture was stirred for one hour at 30'C.8.9 g (1.4 mmol/g carrier) of compiex prepared according to Complex Preparation 1 was added after which the mixture was stirred for 4 hours at 3S-45*C. 0.76g (0.7 mmol/g carrier) of TlCl4 was added and the mixture was stirred for 5 hours at 45'C. The catalyst was dried at 45-80°C for 3 hours. Composition of the catalyst was ; Al 2.4%, Mg 2.0%, TI2.0%, CI 12.5%. The polymer was prepared as In Comparative example 1, Comparative Example 3 Production of the Pipe Materiel: The material was produced according to Comparative Example 1, except that a catalyst was prepared on a 20pm silica carrier. Also, the material targets were changed to some extend. In the first stage, material having MFR2= 300 was produced at a rate of 32 Kg/h. The gas phase reactor was operated so that the production was 39kg/h, MFR21 of the final material was 9 and density was 948. The polymer was then blended with additives including an additive containing carbon black to give the material a black colour. The material was then palletized. The dispersion was then determined from the black pellets according to the procedure described earlier. Table 1 shows some data of the material. 3.7 0 (1.0 mmol/o carrier) of 20% EADC was added to 5.9 o of Sylopol 5510 sitica/MgClz carrier and the mixture was stirred for one hour at 30°C. 5.7 g (0.9 mmol/g carrier) of complex prepared according to Complex Preparation 1 was added and the mixture was stirred for 4 hours at 35-45°C. 0.6 g (0.55 mmol/g carrier) of TICU was added and the mixture was stirred for 5 hours at 45*C. The catalyst was dried at 4S-80°C for 3 hours. Composition of the catalyst was: Al 1.8%, Mg 3.9%= Tl 2.1%= CI 18.5%. The polymerization was performed as in Comparetiva example 1. Example 2 The catalyst was prepared according to Example 1, with the exception that a carrier having 20µm average particle size was used. The bimodai polyethylene material was produced according to Comparative Example 1. Table i shows process and evaluation data. Example 3 The catalyst was prepared according to Example 1, with the exception that a carrier having 20 µm average particle size was used. The bimodai polyethylene materiel was produced according to Comparative Example 3. Table 1 shows process and evaluation data. The catalysts have been tested in bimodal Loop-Gas-Phase process under fixed split and loop melt index. Flow rate ratio (FRR) has been calculated as the ratio of two MFR values measured using different loads, FRR21/5 = MFR21/MFR5. The number of gels was calculated from film blown to film with pilot line. Comparative results to pilot film line were also obtained from the film analysis with large scale film lines. The representative polymer lots were characterized by rheology, where SHI SI/300 comparison is made to polymer with same molecular weight. Measurements were made on Rheometrlcs ROA II at 190°C. Complex viscolty (n*) together with storage modulus (G') and modules (G") as a function of frequency (w) or complex modulus (G*) were obtained. Complex viscosity (n*) as a function of complex modulus (G*) corresponds to viscosity as a function of shear stress and its shape is independent of MW. SHI calculated from this function can be used as a measure of MWD. We Claim:- 1. A two-stage process for the polymerization of ethylene comprising a loop reactor stage and a gas phase rector stage, Wherein a polyethylene composition, which has a molecular weight distribution expressed as SHI5/300, which Is the ratio of the complex viscosity at a complex modulus value of 5kpe to the complex viscosity at a complex modulus value of 300kpa of higher than 60 and a low gel level meaning that when a film is made of the polyethylene composition it has a number of gels in the size class 0.3 - 0.7 mm of the lower than 20 for a film area of 210 mm by 297mm, and no gels of larger size than 0.7mm, is produced by means of a high activity catalyst component, prepared by the steps of reacting; a support comprising a magnesium halide compound having the formula (1): wherein R is a C1-C20 alky I or a C7-C26aralkyl, each same or different X is a halogen, and n is an integer 1 or 2, an alky I metal halide compound having the formula(2): wherein M is B or Al, each same or different R1 is a C1-C10 alkyl, each same or different X1 is a halogen, m1 is 1 or 2, n1 is 1 or 2 when m1 is 1, or n1 is an integer from 1 to 5 when m1 is 2, a magnesium composition containing magnesium bonded to a hydrocerbyl and magnesium bonded to a hydrocarbyl oxide, said magnesium composition having the empirical formula (3): wherein each same or different R2 is a C1-C20 alkyl, each same or different R3 is a C1-C10 alkyl, n2 is between 0.01 and 1.99, and a titanium hallde compound having the formula (4): wherein each seme or different R4 Is a d-C20 aikyl, each same or different X2 Is a halogen, n3 is 0 or an integer 1-3, and Ti is quadrivalent titanium. 2. A process according to claim 1, Wherein the catalyst component preparation comprises the subsequent steps of: a) providing said support comprising a magnesium halide compound having the formula (1), b) contacting said support comprising a magnesium halide compound having the formula (1) with said alkyl metal halide compound having the formula (2), to give a first product, c) contacting said first product with said magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide and having the empirical formula (3), to give a second product, and d) Contacting said seconds product with said titanium halide compound having the formula (4). 3. A process according to claim 1-2, Wherein the said support is In the form of particles, the size of which is from 1µm to 1000pm, preferably from 10µm to 1000µm. 4. A process according to any of claims 1-3, Wherein the said magnesium halide compound having the formula (1) is a magnesium dihalide, preferably MgCI2. 5. A process according to any of claims 1- 4, Wherein the said support a magnesium halide compound having the formula (1) also comprises an inorganic oxide. 6. A process according to any of claims 1- 3, Wherein the said inorganic oxide Is an inorganic oxide having surface hydroxy Is, such as silica, alumina, silica- alumina, magnesia and mixtures thereof, preferably silica. 7. A process according to any preceding claim Wherein the said support comprises particles having a core comprising said inorganic oxide and a shell comprising said magnesium halide compound. 8. A process according to claim 5,6 or 7, Wherein the said support, the amount of said magnesium halide compound having the formula (1), expressed as per cent magnesium Mg calculated on the weight of the support, is 1-20%, preferably 2-6%. 9. A process according to any preceding claim, Wherein the in said alkyl metal halide having the formula (2), independently, M Is Al, each same or different R1 is a Ci-C6 alkyl, each X1 Is a chlorine, n1 is 1, and m1 is an integer 1 or 2. 10. A process according to claim 9, Wherein the said alkyl metal halide compound having the formula (2) is an alkyl aluminlmum dlchloride, e.g. ethyl-alum imium dichloride. 11. A process according to any of claims 2 to 10, Wherein the in step b), of the catalyst component preparation, said support comprising a magnesium halide compound having the formula (1) is contacted with a solution of said alkyl metal halide compound having the formula (2) in an essentially non-polar solvent, preferably a non-polar hydrocarban solvent, most preferably a C4-C10 hydrocarbon. 12. A process according to claim 11, Wherein the the concentration of said alkyl metal halide compound having the formula (2) in said non-polar solvent Is 1- 80% by weight, preferably 5-40% by weight, most preferably 10-30% by weight. 13. A Process according to claim 11 or 12, Wherein the total volume of the alkyl metal hallde compound (2) solution is not exceeding the pore volume of the support. 14. A process according to any of claims 2 to 12, Wherein the said step b), said support comprising a magnesium halide compound having the formula (1) is contacted with a solution of said alkyl metal halide compound having the formula (2) in a ratio moles of said alkyl metal halide to grams of said support of between 0.01 mmol/g and 100 mmol/g preferably 0.5 mmol/g and 2.0 mmol/g. 15. A process according to any of claims 2 to 14, Wherein the said step b), said support comprising a magnesium halide compound having the formula (1) is contacted with a solution of said alkyl metal halide compound having the formula (2) in a molar ratio of said alkyl metal halide compound (2) to said magnesium halide compound (1) of between 0.01 and 100 mol/mol, preferably 0.1 mol/mol and lOmol/mol, most preferably 0.2 and 3.0 mol/mol. 16. A process according to any preceding claim, Wherein the said magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide having the empirical formula (3), each same or different R2 Is a C2-C10 alkyl. 17. A process according to any preceding claim, Wherein the said magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide having the empirical formula (3), each same or different R3 is a C3-C2o alkyl, preferably a branched C4-C10 alkyl, most preferably a 2-ethyl-l-hexyl or a 2-propyl-l-pentyl. 18. A process according to any preceding claim, Wherein the said magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide having the empirical formula (3), is a contact product of a dialkyl magnesium having the formula (5): Wherein each same or different R2 Is defined as above, and an alcohol. 19. A process according to claim 18, Wherein the said dialkyl magnesium having the formula (5) is dibutyl magnesium, butyl ethyl magnesium or butyl octyl magnesium. 20. A process according to any preceding claim, Wherein the said magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide having the empirical formula (3), is a contact product of a dialkyl magnesium and an alcohol having the formula (6): wherein each same or different R3 Is the same as above. 21. A process according to claim 20, Wherein the said alcohol having the formula (6) is a 2-alkyl alkanol, preferably 2-ethyl hexanol or 2-propyl pentanol. 22. A process according to any of claims 18-21, Wherein the said magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide having the empirical formula (3) is a contact product of a dialkyl magnesium and an alcohol in a molar ratio alcohol to dialkyl magnesium of 0.01-100 mol/mol, preferably 1.0-5.0 mol/mol, more preferably 1.7-2.0 mol/mol, most preferably 1.8-1.98 mol/mol. 23. A process according to any of claims, 2-22, Wherein the in step c), said first product is contacted with said magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide and having the empirical formula (3). 24. A process according to any of claims 2-23, Wherein the step c), said support or, optionally, said first reaction product, is contacted with said magnesium composition containing magnesium bonded to a hydrocarbyl and magnesium bonded to a hydrocarbyl oxide and having the empirical formula (3) in a ratio moles of magneslum/g of the support of between 0.001-1000 mmol/g of the support, preferably 0.01-100 mmol/g of the support, most preferably 0.1- 10 mmol/g of the support, (g of the support means, in the case of said first reaction product, the support which was used as starting material for the first reaction product.) 25. A process according to any of claims 2-24, Wherein the step c), said support or said first product is contacted with a solution of said magnesium composition (3) in a hydrocarbon. 26. A process according to claim 25, Wherein the concentration of said solution is 5-60% by weight. 27. A process according to claim 25 or 26, Wherein the volume of said solution is about two times the pore volume of the support or said first product 28. A process according to any preceding claim, Wherein the said titanium halide compound having the formula (4), R4, Is a C2-C8 alkyl, preferably a C2-C6 alkyt. 29. A process according to any preceding claim, Wherein the said titanium halide compound having the formula (4), X2 is chlorine. 30. A process according to any preceding claim, Wherein the said titanium halide compound having the formula (4), n3 ls 0. 31. A process according to any preceding claim, Wherein the said titanium halide compound having the formula (4) is titanium tetrachloride. 32. A process according to any preceding claim, Wher ein the addition to said titanium compound having the formula (4), a titanium compound having the formula (7): wherein each same or different R5 is a C1-C20 alkyi, preferably a C2-Ce alky! most preferably a C2-C6 alkyit each same or different X3 is a halogen, preferably chlorine, n4is an integer 1-4, and Ti is quadrivalent titanium, is reacted. 33. A process according to ciaim 32, Wherein the titanium tetrachloride and titanium tetra C1-C6-elkoxide ere reacted. 34. A process according to any of claims 2-33, Wherein the said second reaction product is contacted with said titanium compound having the formula (4) In a ratio moles of said titanium compound/g of the support of 0.1-10 mmoi/g of the support, preferably 0.1-2 mmoi/g of the support 35. A process according to any of claims 2-34, Wherein the said second reaction product Is contacted with said titanium compound having the formula (4) in a ratio moles of said titanium compound/total moles of the magnesium of 0.05-2 mol/mol, preferably 0.1-1.2 mol/mol, most preferably 0.2-0.7 mol/mol. 36. A process according to any of claims 1 - 35, together with a co-catalyst having the formula (9): wherein each R6 is independently a C1-C20 alkyi, preferably a C2-C10 alkyi, most preferably a C2-C6 aikyl such as ethyl, X is a halogen, preferably chlorine, n is 1 to 3, more preferably 2 or 3, most preferably 3.

Documents:

in-pct-2000-472-che-abstract.pdf

in-pct-2000-472-che-claims filed.pdf

in-pct-2000-472-che-claims grand.pdf

in-pct-2000-472-che-correspondence others.pdf

in-pct-2000-472-che-correspondence po.pdf

in-pct-2000-472-che-description complete filed.pdf

in-pct-2000-472-che-description complete grand.pdf

in-pct-2000-472-che-form 1.pdf

in-pct-2000-472-che-form 19.pdf

in-pct-2000-472-che-form 26.pdf

in-pct-2000-472-che-form 3.pdf

in-pct-2000-472-che-form 4.pdf

in-pct-2000-472-che-form 5.pdf

in-pct-2000-472-che-other documents.pdf

in-pct-2000-472-che-pct.pdf